1. Field of the Invention
The present invention relates to an antibiotic zeolite and an antibiotic resin composition containing the zeolite and more particularly to an antibiotic zeolite which does not cause discoloration with time.
2. Description of the Prior Art
Heretofore, there have been known such inorganic antibiotics as silver-supporting active carbon as disclosed in Japanese Patent Un-examined Publication No. 49-61950 and such organic antibacterial or antifungus agents as N-(fluorodichloromethylthio)-phthalimide.
However, in the former (inorganic antibiotics), silver ions are rapidly leached out therefrom and, therefore, it is difficult to attain a sustained antibiotic effect.
On the other hand, among the latter (organic antibacterial or antifungus agents), some of them have no antibacterial effect depending on the kinds of bacteria or mold (in other words, these being inferior in general purpose with respect to the kinds of bacteria or mold). Further even those having heat resistance sometimes cause decomposition or evaporation during kneading them into a resin at a temperature of 150.degree. to 300.degree. C. This leads to the reduction of antibacterial effect.
For the purpose of eliminating the aforementioned disadvantages associated with these conventional antibiotics, there have been developed so-called antibiotic zeolites which comprises an antibiotic component supported on zeolite (see, for instance, Japanese Patent Published for Opposition No. 61-22977 and Japanese Patent Un-examined Publication No. 60-181002).
The aforesaid antibiotic zeolite is certainly an excellent antibiotic agent which exhibits a sustained antibiotic action when left to stand in water or in the air and does not cause change of properties during kneading it with a resin. However, such an antibiotic zeolite suffers from a disadvantage that it gradually causes discoloration in the course of time. This discoloration exerts no influence on the antibiotic effect of the antibiotic zeolite and, therefore, the antibiotic zeolite is still an excellent antibiotic agent. However goods in which such an antibiotic zeolite is incorporated sometimes causes discoloration. This leads to remarkable reduction of their commercial value depending on the kinds thereof.